The state of the art includes steam cleaning apparatus including a steam production unit consisting essentially of a boiler housed in an autonomous containing structure, usually equipped at the lower part with wheels or suchlike, equipped with a flexible tube to which a desired cleaning accessory can be optionally associated.
These containing structures are usually very large and very heavy, in proportion to the size of the boiler, so that the apparatus is sufficiently autonomous for the required cleaning operations.
This makes the apparatus less practical to use, more difficult to transport and less manageable.
It is well-known, for example, that users find considerable difficulty in cleaning extensive or vertical surfaces, since such operations involve dragging or lifting the containing structure from one place to another.
Moreover, when they are not in use such appliances require ample storage space. Furthermore, appliances of this type use a great deal of energy because they have to keep a large quantity of water at evaporation temperature.
Moreover, they are very dangerous to use because the boiler has to be maintained under pressure.
Furthermore, in apparatus known to the art the steam generated by the boiler is delivered to the cleaning accessories through corrugated pipes, or similar, of great length; this causes the steam to lose pressure and therefore the efficiency of the cleaning action is lessened.
Moreover, with such apparatus it is possible to regulate the outlet pressure of the steam, but it is not possible, when using the same accessory, to differentiate the cleaning action to adapt it to the type and/or size or conformation of the surface which is to be cleaned or the degree of cleaning required.
Another problem of such appliances as are known to the art is that a great deal of time is wasted every time the boiler has to be refilled; this is because, before refilling, the user must wait until the pressure inside the boiler has dispersed and then, after refilling, the user must again wait until the water is transformed into steam.
The refilling action itself is moreover not very practical in that it usually requires the use of funnels or appropriate recipients to transport the water from the delivery area to where the cleaning apparatus is being-used.
Another problem is that, when the apparatus is connected with cleaning cloths or rags, it is necessary to use predetermined elements, which cannot be exchanged with other, more common ones, and this causes an increase in costs.
In order to solve, at least in part, the afore-mentioned problems, there have been proposals for compact cleaning devices equipped with incorporated means to produce steam.
DE-A-3031263, for example, describes a cleaning apparatus, used in particular to clean carpets or suchlike, including a closed containing structure sub-divided into two super-imposed chambers communicating with each other by means of an adjustable valve.
The upper chamber functions as a reservoir for the cold water and the lower chamber is used to produce steam.
For this purpose, the lower chamber is equipped with a heated plate equipped with a plurality of through holes associated with respective steam delivery holes on the lower face, that is to say, the face in contact with the surface to be cleaned, of the containing structure.
The water contained in the upper chamber passes through the valve into the second chamber and, as it comes into contact with the heated plate, is transformed into steam which comes out through the delivery holes.
This cleaning apparatus has the disadvantage that the valve which regulates the flow of water to the heated plate is difficult to set.
Moreover, this method of forming steam using a heated plate does not guarantee that all the water introduced into the second chamber can be changed into steam, with a consequent leakage of water from the delivery holes and therefore an excessive dampening of the surface to be cleaned.
In addition, the heated plate is quickly covered with scale, and thus loses its heating power and drastically reduces its steam producing capacity.
This cleaning apparatus, moreover, is not suitable for cleaning limited surfaces or corners or areas. which are difficult to get at, since the steam delivery holes are concentrated in the central part of the lower face.
The European patent EP-A-0,253,910 describes a steam cleaning apparatus comprising a longitudinal body defining inside itself a tank to contain water associated by means of a pump which can be selectively activated with a boiler suitable to generate instant steam and arranged substantially in correspondence with the foot of the apparatus.
The outlet of the instantaneous boiler is associated with a steam delivery nozzle with which cleaning accessories such as brushes, nozzles or otherwise can be associated when so desired.
This apparatus is not at all practical, difficult to use and manoeuvre because of the size of the handle and the weight of the water tank, which is arranged on the handle itself and has to be supported by the user during the cleaning operations.
IT-B-1194529 teaches to provide a washing apparatus of the type as in DE-A-3031263, but with a tank applied on the handle.
According to a variant there is an auxiliary tank which is located adjacent to the mini-boiler in such a manner as to be pre-heated thereby.
This document teaches to obtain a washing apparatus which is complex in structure and in operation due to the inclusion of two different tanks which can be applied on different occasions when desired.
This creates problems for the user, and also problems of water tightness and duration of the tank in contact with the mini-boiler.
With this solution it also takes a long time for the water to be brought to evaporation.
EP-A-0,842,631 describes a steam cleaning apparatus equipped with a handle connected at the end to a closed containing structure whose lower face is suitable to be rested on the surface to be cleaned.
The closed containing structure houses an inseparable boiler which produces steam at atmospheric pressure by means of electric resistors.
The closed containing structure is equipped at the upper part with a filling aperture communicating with the boiler and its dome-shaped top cooperates with the upper end of a conduit whose lower end is associated with a collector provided with a plurality of steam delivery holes arranged in a single line.
This arrangement of the delivery holes gives an effective cleaning action on extensive surfaces but it is not very suitable for cleaning edges, corners or more generally limited surfaces or surfaces with restricted access.
Moreover, in this device it is not possible to vary the manner in which the steam is delivered so as to give different levels of cleaning and/or to adapt the impact and geometry of the steam delivery to the type of surface to be cleaned.
This cleaning device, moreover, has the disadvantage-that, in order to fill it, it requires a funnel and a measuring device, which entails inconvenience and frequent interruptions for the user, especially considering the limited capacity of the boiler.
Another disadvantage is the time wasted while waiting for the electric resistors to transform the water contained in the boiler into steam.
Furthermore, the device has outer parts which over-heat during use, such as the cap on the tank and the edge of the boiler, which can scald the user during refilling operations.
Moreover, this device needs to be disconnected from the electricity supply while refilling is carried out, in order to avoid the danger of electrocution.
This is an intrinsic danger of all devices described in the prior art documents cited above.
Another disadvantage is that the device requires special cloths to be used which must therefore be kept constantly to hand and replaced, after use, in places where they can easily be found.
The present applicant has designed and embodied this invention to overcome the shortcomings of the state of the art and to provide further advantages.